Density Functional Theory Study of Water Adsorption on the CoO (100) and CoO (110) Surfaces

Abstract

In this study, density functional theory was used to identify the optimum adsorption sites of H2O molecule on the CoO(100) and CoO(110) surfaces. The adsorption of H2O molecule is the first step in water molecule splitting on a catalytic surface. CoO bulk crystals were optimised by using generalised gradient approximation-Perdew-Burke-Ernzerhof functional methods through spin orbital interaction calculations. Band structure calculation results show that the indirect and direct bandgaps are 0.23 and 1.6 eV, respectively, which are similar to the reported experimental bandgap. The CoO(100) and CoO(110) surfaces were created from the optimised bulk structure. The CoO(100) surface contains 13 atoms Co vacancy, whereas the CoO(110) surface contains 15 atoms Co vacancy on the top layer surfaces. The adsorption energy of H2O on the CoO(100) and CoO(110) surfaces was calculated on the basis of eight configurations. The optimum adsorption energy (5.123 eV) of H2O on the CoO(100) surface is in Model 5. Meanwhile, the optimum adsorption energy (2.810 eV) of H 2O on the CoO (110) surface is in Model 6. This result indicates that H2O is easier to absorb on CoO(110) than on CoO(100), and agree to the experiment result reported.

Effect of External Electric Field Applied to Bilayer Graphene Bandgap: Density Functional Theory Study

“…In this study, we investigated the effect of applied external electric field potential on the band gap opening of bilayer graphene theoretically using density functional theory (DFT) calculation. As known, most DFT software today has been equipped with a function to calculate various properties, including the effect of an external electric field applied on the electronic structure of a system molecule in various directions [9][10][11]. Here, we compare the three different level of DFT, that is GGA-PBE, GGA-PW91, and LDA-CAPZ on the bilayer graphene stacking.…”